Opportunistic depredation of songbird nestlings by female praying mantids (Mantodea: Mantidae)

Abstract Praying mantids (class Insecta, order Mantodea) are a group of predatory insects comprising approximately 2500 described species, that occur across all continents except Antarctica, with the greatest species diversity in tropical and subtropical regions. Mantids predominantly prey on other invertebrates but are known to feed on small vertebrates. During April and May 2021, we observed mantid feeding events in Manujan County, Kerman Province in southern Iran. Two distinct feeding events were observed where female European Mantids (Mantis religiosa) preyed on Purple Sunbird (Cinnyris asiaticus) and Crested Lark (Galerida cristata) nestlings. In addition, we collated information from online searches of mantids feeding on nestlings elsewhere in the world, revealing two more observations. In Taiwan, a Giant Asian Mantid (Hierodula patellifera) was recorded preying on a nestling Warbling White‐eye (Zosterops japonicus) and in Brazil, a mantid (Stagmatoptera sp.) was recorded feeding on a nestling White‐throated Seedeater (Sporophila albogularis). To date, the only existing scientific evidence of praying mantids feeding on passerine nestlings was recorded in 1922. We propose two potential explanations for the observed trophic interactions between mantids and passerine nestlings: (1) during egg production female mantids, especially those in poor physical condition, may opportunistically feed on nestlings in order to increase fecundity via nutrient gain and (2) mantids may initially be attracted toward the nest by parasitic or coprophagous insects, as a result of poor nest sanitation, and subsequently prey on nestlings after detecting movements. Our unusual observations represent the first records of praying mantids feeding on nestling passerines in nearly 100 years.

observed where female European Mantids (Mantis religiosa) preyed on Purple Sunbird (Cinnyris asiaticus) and Crested Lark (Galerida cristata) nestlings. In addition, we collated information from online searches of mantids feeding on nestlings elsewhere in the world, revealing two more observations. In Taiwan, a Giant Asian Mantid (Hierodula patellifera) was recorded preying on a nestling Warbling White-eye (Zosterops japonicus) and in Brazil, a mantid (Stagmatoptera sp.) was recorded feeding on a nestling White-throated Seedeater (Sporophila albogularis). To date, the only existing scientific evidence of praying mantids feeding on passerine nestlings was recorded in 1922. We propose two potential explanations for the observed trophic interactions between mantids and passerine nestlings: (1) during egg production female mantids, especially those in poor physical condition, may opportunistically feed on nestlings in order to increase fecundity via nutrient gain and (2) mantids may initially be attracted toward the nest by parasitic or coprophagous insects, as a result of poor nest sanitation, and subsequently prey on nestlings after detecting movements. Our unusual observations represent the first records of praying mantids feeding on nestling passerines in nearly 100 years. Kerman Province, southern Iran. We used a Canon 5D Mark п professional camera to record predation events. Mantids were identified to species-level using Giglio-Tos (1927) and .
In addition to our field observations, we conducted online searches on Google (www.google.com) to collate information on mantids predating nestling birds documented by members of the general public. We searched using the following key search terms: "predation", "hunting", "chicks", "nest", "bird", "mantid" and "mantis".
Beside English, online searches were performed in Arabic, Chinese, French, Italian, Persian and Spanish.
From our field observations, we documented two events where female European Mantids (Mantis religiosa) were observed feeding on nestling birds. The female mantids fed on Purple Sunbird (Cinnyris asiaticus) and Crested Lark (Galerida cristata) nestlings that were approximately a few days old (Table 1; Figure 1). The Purple Sunbird nest was located on a Christ's Thorn Jube tree (Ziziphus spina-christi), whereas the Crested Lark nest was located at ground-level. On both occasions, the female mantids appeared to prey on nestlings opportunistically. The mantids were located close to the nest locations and hunting was initiated by the movements of the nestlings within the nest. We suggest that the mantids were behaving opportunistically as prior to this, the mantids appeared unaware of the nestlings' presence. Once the mantids seized the chicks, they began feeding and dragged the chicks out of the nests.
Our online searches also found two additional records of praying mantid predation on nestlings. In Taiwan, a Giant Asian Mantid (Hierodula patellifera) was recorded preying on a nestling Warbling White-eye (Zosterops japonicus) and in Brazil, an unidentified mantid (Stagmatoptera sp.) was recorded feeding on a nestling Whitethroated Seedeater (Sporophila albogularis; Table 1). Both online observations occurred on trees and nestlings appeared older than those recorded in Iran, i.e., chicks were feathered, however had yet reached the fledgling growth stage. Mantids were also recorded dragging nestlings from the nests.

| DISCUSS ION
Our field observations represent the first recorded feeding events between praying mantids and passerine nestlings in nearly 100 years. To date, all mantids recorded feeding on birds have been female (Nyffeler et al., 2017). These unusual observations may be due to two potential explanations. First, during the egg production period, female mantids have been known to use sexual cannibalism as a foraging strategy to increase fecundity, especially those in poor physical condition (Barry et al., 2008). A passerine nestling may provide high nutritional value for a female mantid in poor condition. Therefore, in order to increase fecundity, female mantids may take advantage of nestling birds for nutrient gain. Second, mantids may be attracted to nests with poor sanitation, i.e., lack of removal of fecal sacs by parents, resulting in increased abundances of parasitic or coprophagous insects, e.g., Diptera (Ibáñez-Álamo et al., 2016).
Subsequently, the praying mantids may then prey on nestlings after detecting movements from the young birds.
Despite this, mantids have been known to select optimum hunting sites, e.g., "sitting-and-waiting" at vantage points in areas with high prey abundance, observed in Chinese (Tenodera sinensis), Bordered (Stagmomantis limbata) and European Mantids hunting at hummingbird feeders (Nyffeler et al., 2017). Furthermore, other scents or natural lures may indirectly attract mantids to potential prey sources, e.g., a European Mantid nymph was observed hunting sarcophagid insects that were attracted by the scent of dog feces in Birkirkara, Malta (Cassar, 2020), or in this case to nests with poor sanitation and increased parasitic or coprophagous insect abundances (Ibáñez-Álamo et al., 2016).

Previous literature and anecdotal evidence have shown that
European, Giant Asian and Stagmatoptera Mantids are capable of catching and feeding on adult passerines in flight (Browne, 1899;Nyffeler et al., 2017;Ridpath, 1997). However, four bird species No.